The study is complete. A total of 32 subjects were enrolled in the above study. Twenty-Five have undergone normal completion, and seven were withdrawn. Of the 25 subjects who completed the study, 9 were receiving an EFV-based regimen, 8 were not receiving antiretroviral therapy, and 8 were receiving an ATV/r -based regimen. Safety data from this protocol are as follows: In summary, 32 adverse events (90 episodes) occurred among 32 subjects. Forty-three of the 90 adverse event episodes were categorized as unrelated to atovaquone; 2 were categorized as definitely related to atovaquone; 11 were recorded as probably related; 27 were recorded as possibly related to atovaquone and 7 were recorded as unlikely related to atovaquone. Ten of the adverse event episodes that were possibly related, and 1 of the adverse event episodes that was probably related to atovaquone were Grade 2, all other events whether definitely related, possibly related, or unlikely related were Grade 1. All plasma samples have been batched and will be analyzed for atovaquone concentrations via MS/HPLC shortly after the assay is fully validated. There are currently no pharmacokinetic data available for this investigation.